Production of hydrocarbon synthesis gas



Patented Sept. 2, 1952 STATES PATNT ori-Fi 'Bertrand J. Mayland, Bartlesville, Okla., as'signor l `to Phillips Petroleum Company, Va corporation of Delaware zpoiaims. (o1. 260g-@Eisley 1 This `invention, relates to the treatment oi naturalgas to'produce asynthesis' gas, that is, la gasfcontainingliydrogen and carbon monoxide. In "one oi fit-s veinbodiments kthe invention provides a process for the production of a synthesis gas haVinga-low rat-io of hydrogen to carbonmonoxide and 'a synthesis ga'sjfha'ving a relatively high-ratio'of '-hycro'gen tocarbon monoxide. In another embodiment the invention provides a process for the loroduction of a 'synthesis gas having'a'low ratio of hydrogen to carbon monoxide from 'a single vstream of natural gas and oxygen, or fair,"Witl 1'out the formation of any byproductsor -n iaterials 'unutlizable in the process. In'stillanother embo dinie'nt ofthe invention there is provided 'fanu'nit` `ary proee'ssi'for the production of 'eherriicals' such fasi Talfiehydes, talcollols, etc., fromnatural gas.

The production of vsynthesis gas, Va mixture yof hydrogen and 'cfarbon monoxide, is a Well known art. It jis known to produce synthesis gas from natural gas by the partial oxidation thereof with oxygenlor'air. The gas thus obtained Will usually have Ta "hydrogen to carbon monoxide ratio of somewhatfless than two, the exact value depend-r 111g ii-loonV the composition 'of the gas, operating condition and the relaftivequantities present of the 'tworactantsf- Y' v Synthesis gases loi various hydrogen to carbon mono'ide sis lp1 cess aratiojoi hydrogen to carbon monoXid-eo two isdesired. 'On the other hand in the x0 process for the production of valuable chemicals from certain hydrocarbons aratio of hydrogen to'cafoonfn ro'r'roxide ofthe lorder of 'one is desired.

The prior art employs a number of .different methods to varytheratio o f'hydrogen to carbon monoxidein A'sy nthesis gas'. Thus', the ratio can 'cr"` sed Aby adding steam to the reactants epartiaijcombustion of the natural gas. It can 'also be ncieased by effectingthe water gas shift reaction on the products of the partial combustion over a suitable catalyst With Yenough steam to cause the desired shift. Also, the ratio of thejhydrogn tojcarbon monoxide can be reducedjey vtheaddition of carbon dioxide tothe reactantsin the production of the synthesis gas. flflhisfmethodjof reducing the ratio of the hydrogen -to carbon monoxide in a synthesis gas is undesirable because ofl Xcessive c'arbon deposi# tion'whi'ch' occurs or becauseof the largeexcesses of the rather? expensive carbon dioxide which must be'u'se-d. Slt isfevidentfrom then'atures' or" all of 'the-foregoing'methods of the' art for-altering the hydrogen 'to 'ca bonmonoxide'ratio 'ofa synthesis gas that vsi de-reactior-is-fresulting 'in un-` Wanted or undesirable linaterialswith concomitant Wastageofstarting materials will occur? in each andparticularly that inthe known method for reducing this ratio theoarbon '-dioxide, iwhioh is used, 'iseiipensive nand ri'iu'st-v be used Vlarge excesses. s

rAccording to this T'invention 'there is rprin/ided a process for altering the 4hydr en tocarbon monoxide ratioof fa synthesis gas particularly to `reduce the saine, employing purely Y'physical means thereby avoid-ing jenurely the unwanted materials jform'edjin *the fprior Vart processes as well as the non'corni-tant Wasta'ge 'and great e'xpense Whichjhasbeen involved.

'lurthe'rmore,A At ere is 'rovided vaccord-ing to this invention,` a -pijx'icesfs for the \prodution of "a high vhydrogen-'to-canbon monoxide ratio synthe# sis gas `forming 'at the V'saune time one ofajlovv hydrogen to Dcarbon monoxide ratio employ-ing a novel conibinationoi-'step's to this end and in such lmanner thatjboththe-fhigh and low ratio gases canbe used Without 'any further intermediateprocessingjsteps to produce valuable hydrocarbons and/orhchemfical products;Av

AStill further accordingtgthis invention lthere is provided a novel combination oiisteps Yto effeet "the production fof i said 'hydroarows and chemicals fromsa'iijl highandglow vratio gases. V

It vlilas been found that hydrogenand carbon monoxide; .in asylnthess eases derived kfrom La synthesis :gas producer 'will c lilius efat vvid dif'-y ferent rat'es g through ajsuitable porous r pa Il: It has lalso been found 'that thejhydroeenjwill diffuse at a ratesojra'pd in respect 9Lthera'te1of diffusion' 0f 'the .Carbon monoxide, .inthe .synthe sis gas, that it bcomee possibletoiform ia ,stream substantially richerv Vin' ihydroge'n than tliefsyn-y thesis gas Vand fa stream, c' o nsiderabltr poorer 'in hydrogen thanthe synthesis gas Thus, according totlis invention.'.`the e vided a Iproc'zes's Yf of'rgtl'ie altering of the 'ratiofof hydrogentvearbtn monoxide in 'a synuiesiv "g" b'ysubgeeung the same-to adhesions .und which the components f Will d''use 4at Widely different ratesjth ugh 'permeable partition, or permeable phys'ial dary,.composed of a suitable gpo'rous material Ito form twostreams of gasesyfo'ne Yricher Vin hydrogen and ,anotherpoorer in hydrogen tlia'n the ,starting synthesis gas. No chemicaireetio is 'involved fand 'the altration of the hydrogen to carbon monoxide ratio occurs without any attendant formation of unwanted materials or wastage of synthesis gas or use of other expensive starting materials required in the prior-art;Av

As the partition-member there can be employed a number of different materials among which are screens woven from wires, ribbons,

heat resistant cloths, etc. Perforated or slotted plates can be employed. Also, certain unglazed refractory materials such as silica, alundum, porcelain, etc., can be employed.

To operate the process in a Vcontinuous manner with a high degree of eciency and to prevent loss in diffusion rate provision is made for an entrainer substance, for example steam, or even natural gas, to remove the diffused gas from the side of the partition to which it has diifused.

To more fully set forth the invention and to illustrate the same in one of its embodiments reference is now made to the drawing in which is shown diagrammatically-a process for the production of both a low hydrogen to carbon monoxide ratio 'synthesis gas and a high hydrogen to carbon monoxide ratio synthesis gas, using as a starting gas a synthesis gas produced by the partial combustion of natural gas with oxygen, or air, to produce valuable hydrocarbons and chemicals in a unitary processV having certain features and possessing certain advantages not heretofore attainable. In the drawing natural gas is fed together with oxygen or air to combustor or reactor I in which partial oxidation occurs to produce synthesis gas in a manner known to the art. From reactor I the synthesis gas is passed into heat exchanger IA, cooled to below 1000 F., and passed to section 2 of a diffusion unit 3. Diiusion unit 3 contains a suitable diffusion partition 4. Hydrogen and carbon monoxide will diffuse through partition 4 at different rates such that the hydrogen content of the gas in section 2 will Aloesubstantially reduced and a gas enriched in hydrogen will be formed in section 5 of the unit. The low hydrogen content gas is withdrawn from section 2 through line 6 for use asdescribed below. The gas enriched in hydrogen is Withdrawn from section 5, through line 1.V To assist in the withdrawal of the gas enriched in hydrogen and to maintainA a high diffusion rate through partition 4, an entrainer medium, in this casev steam, is fed into unit 3 through line d and caused to impinge upon partition 4, as shown. The static pressure in sections 2 and 5 is to be maintained substantially the same so that the transfer of gas from one section to the other will take place substantially only by diffusion. A portion ofthe gas withdrawn through line 'l is passed through line 9 to line l0 where it is admixed with and quenches synthesis gas produced in reactor II by partial oxidation of natural gas therein, thus forming a composite synthesis gas having a hydrogen to carbon monoxide ratio of about 2:1. Thus, it is that according to this invention both a synthesis gas ofalow hydrogen to carbon monoxide' ratio and oneof a high ratio can be produced eiciently, readily and without any formation of the unwanted materials `of the prior art or wastage oi starting materials. Y

The composite synthesisgas 4stream formed in line I0 can be withdrawn through cooler I2 and can have a hydrogen to carbon monoxide ratio making it directly usable in a Fischer-Tropsch reaction for the preparationof hydrocarbons.

The ratio of hydrogen to carbon monoxide in the synthesis gas removed from diffusion chamber 3 through line 6 is such that this gas can be used directly in the Oxo process for the preparation of chemicals such as aldehydes and ketones'by reaction with hydrocarbonaolcnic in character, which can be obtained either directly from the Fischer-Tropsch product or by dehydrogenation in zone I4 of Fischer-Tropsch paramns produced in zone I3. Such dehydrogenated hydrocarbonsv are then passed to an Oxo unit I5.

Certain Fischer-Tropsch catalysts, particularly reduced and promoted iron oxide catalysts, produce oleiins in considerable proportions when used to catalyze the synthesis of hydrocarbons from carbon monoxide and hydrogen at about 600 F. This type of catalyst is advantageously used in my process` In such a case, the eiiluent from reactor I3 is passed to separation zone I8. This zone may comprise several conventional separation steps, such as partial condensation, phase separation, fractional distillation, solvent extraction, extractive distillation, etc. The eiiiuent is here resolved into several fractions. A gas fraction comprising hydrogen and methane is withdrawn and may be recycled to reactor I or I I. A liquid hydrocarbon product, which may comprise parairlns or paraims and some of the synthesized olens is withdrawn and further processed to obtain fuels or other products. An aqueous phase containing dissolved oxygenated Icy-products is also'recovered and processed as desired for chemical recovery. A fraction comprising at least one olefin (e. g. hexene-l or octene-1 or a mixture of olens) is passed to Oxo unit I5 for catalytic reaction with carbon monoxide and hydrogen to produce aldehydes and/or alcohols by known methods. A catalyst comprising cobalt and thoria supported on kieselguhr may be used.

It is also within the scope of the invention to recover a fraction comprising one or more parafns in zone I8 and pass this fraction to dehydrogenation zone l4,to obtain additional amounts of olens for the Oxo reaction. Catalytic dehydrogenation at 1000-1200 F. with a chromia-containing catalyst is suitable. The olens produced are freed of hydrogen and other light gases in separation zone I 9 and passed to Oxo unit I5.

. It is, of course, within the scope of the invention to produce all the olen feed to Oxo unit I5 bythe Fischer-Tropsch synthesis in reactor I3. It is also within the scope of the invention to produce a predominantly parainic synthesis product, as by use of a cobalt catalyst, and produce the entire olefin charge for unit l5 by dehydrogenation in zone I4. l

Thus, according to this invention a unitary process is provided for the production of chemicals from natural gas.

If desired, some of the gas withdrawn from the diiiusion unit through line 'l can be passed through line I6 to the second combustor or reactor l I wherein it will serve to still further increase the hydrogen to carbon monoxide ratio of the synthesis gas produced therein. Y

According, to Vthe invention it has been found that some or all of the sweeping medium employed can be natural gas, or its equivalent, and when it is employed as such, that no appreciable adverse reaction occurs during the sweeping of the hydrogen rich synthesis gas from the diusion unit. The natural gas may be used either alone or together with steam. It has also been found that the admixture of the natural gas Ei sweeping medium and the hydrogen-rich synthesis gas which results, when natural gas is einployed, can be passed directly, without any intermediate treatment, intol reactor ii wherein in the presence of steam the water gas shift reaction to produce more hydrogen will occur simultaneously with the partial combustion of the natural gas` Without oxidation of the hydrogen in the admixture oi? an extent to prove disadvantageous to the overall operation.

Thus, according to the invention, some or all of the entrainer gas employed may be natural gas in which event substantially all of the eiiluent in line 7 can be passed to reactor H through line I6. When natural gas is employed as a sweeping medium it can be introduced through line I7 or at any other convenient place.

The following example is illustrative of some of the principal features of the invention.

Example 100 mols of product obtained in the combustion in reactor (l) consisting of 40 mols of CO and 60 mols of Hz are treated with 165 mols of steam in the diiusion unit. About 20 mols consisting of 15.6 mols of hydrogen and 4.4 mols of carbon monoxide are removed in the steam leaving 80 mols of synthesis gas having a hydrogen to carbon monoxide ratio of 1.25. lT'he steam and hydrogen concentrate are added to the products of combustor (2) in which the amount and composition of synthesis gas produced is about the same as in combustor (1). 120 mols of synthesis gas are obtained having a hydrogen to carbon monoxide ratio of 1.7. Putting some of the steam and hydrogen concentrate in the reac-tant stream to combustor (2) a further increase in the synthesis gas hydrogen to carbon `monoxide ratio can be realized.

I claim:

1. In a process for the preparation of a feed for a Fischer-Tropsch synthesis and for an Oxo catalytic chemical synthesis operation wherein a rst and a second portion of natural gas are subjected to partial oxidation to form a synthesis gas comprising hydrogen and carbon monoxide, and said products of partial oxidation of said second natural gas portion are subjected to Fischer-Tropsch synthesis, the improvement which comprises subjecting products of partial combustion of said first portion of natural gas directly and without intermediate treatment to a diiusion by passing said gas into contact with one side of a porous physical partition; passing an entrainer medium consisting essentially of a third -portion of natural gas over the opposite side of said partition; maintaining substantially the same static pressure on both sides ofthe partition, thus obtaining the diusion of hydrogen and carbon monoxide to said opposite side of said partition, the hydrogen diffusing at a rate substantially greater than the carbon monoxide; withdrawing from said one side of said partition a synthesis gas having a substantially lower hydrogen content than the starting synthesis' gas and from the opposite side of said partition said entrainer medium containing a synthesis gas having a substantially higher hydrogen content than the starting synthesis gas; combining at least a portion of said entrainer medium containing said synthesis gas having av higher hydrogen content than the starting synthesis gas with said products of partial combustion of said second natural gas portion prior to said Fischer-Tropsch synthesis; and mixing olenic hydrocarbons with said synthesis gas having a hydrogen content substantially lower than the synthesis gas treated, thereby forming a feed suitable for Oxo catalytic chemical synthesis.

2. The process of claim 1 wherein at least a portion of said entrainer medium containing a synthesis gas having a substantially higher hydrogen content than the starting synthesis gas is combined with said second natural gas portion prior to partial oxidation.

BERTRAND J. MAYLAND.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,174,631 Snelling Mar. 7, 1916 1,496,757 Lewis et al June 3, 1924 2,159,434 Frey May 23, 1939 2,253,607 Boyd Aug. 26, 1941 2,255,069 Maier Sept. 9, 1941 2,347,682 Gunness May 2, 1944 2,360,463 Arveson Oct. 17, 1944 2,497,898 McGurl Feb. 21, 1950 FOREIGN PATENTS Number Country Date 22,340 Great Britain Dec. 21, 1891 308,792 Great Britain Aug. 11, 1930 OTHER REFERENCES Ser. N0. 373,703, Martin (A. P. CJ, published 55 July 13, 1943. 

1. IN A PROCESS FOR THE PREPARATION OF A FEED FOR A FISCHER-TROPSCH SYNTHESIS AND FORN AN OXO CATALYTIC CHEMICAL SYNTHESIS OPERATION WHEREIN A FIRST AND A SECOND PORTION OF NATURAL GAS ARE SUBJECTED TO PARTIAL OXIDATION TO FORM A SYNTHESIS GAS COMPRISING HYDROGEN AND CARBON MONOXIDE, AND SAID PRODUCTS OF PARTIAL OXIDATION OF SAID SECOND NATURAL GAS PORTION ARE SUBJECTED TO FISCHER-TROPSCH SYNTHESIS, THE IMPROVEMENT WHICH COMPRISES SUBJECTING PRODUCTS OF PARTIAL COMBUSTION OF SAID FIRST PORTION OF NATURAL GAS DIRECTLY AND WITHOUT INTERMEDIATE TREATMENT TO A DIFFUSION BY PASSING SAID GAS INTO CONTACT WITH ONE SIDE OF A POROUS PHYSICAL PARTITION; PASSING AN ENTRAINER MEDIUM CONSISTING ESSENTIALLY OF A THIRD PORTION OF NATURAL GAS OVER THE OPPOSITE SIDE OF SAID PARTITION; MAINTAINING SUBSTANTIALLY THE SAME STATIC PRESSURE ON BOTH SIDES OF THE PARTITION, THUS OBTAINING THE DIFFUSION OF HYDROGEN AND CARBON MONOXIDE TO SAID OPPOSITE SIDE OF SAID PARTITION, THE HYDROGEN DIFFUSING AT A RATE SUBSTANTIALLY GREATER THEN THE CARBON MONOXIDE; WITHDRAWING FROM ONE SIDE OF SAID PARTITION A SYNTHESIS GAS HAVING A SUBSTANTIALLY LOWER HYDROGEN CONTENT THAN THE STARTING SYNTHESIS GAS AND FROM THE OPPOSITE SIDE OF SAID PARTITION SAID ENTRAINER MEDIUM CONTAINING A SYNTHESIS GAS HAVING A SUBSTANTIALLY HIGHER HYDROGEN CONTENT THAN THE STARTING SYNTHESIS GAS; COMBINING AT LEAST A PORTION OF SAID ENTRAINER MEDIUM CONTAINING SAID SYNTHESIS GAS HAVING A HIGHER HYDROGEN CONTENT THAN THE STARTING SYNTHESIS GAS WITH SAID PRODUCTS OF PARTIAL COMBUSTION OF SAID SECOND NATURAL GAS PORTION PRIOR TO SAID FISCHER-TROPSCH SYNTHESIS; AND MIXING OLEFINIC HYDROCARBONS WITH SAID SYNTHESIS GAS HAVING A HYDROGEN CONTENT SUBSTANTIALLY LOWER THAN THE SYNTHESIS GAS TREATED, THEREBY FORMING A FEED SUITABLE FOR OXO CATALYTIC CHEMICAL SYNTHESIS. 